Rabbit Serum (Normal Rabbit Serum, NRS) — Sterile Filtered | EU Origin | SeamlessBio
EU Stock0.2 µm sterile filteredNo MOQCoA included
Normal Rabbit Serum (NRS) is the universal blocking reagent for all immunoassays using anti-rabbit secondary antibodies. Because anti-rabbit secondaries are the most widely used secondary antibodies in biomedical research, NRS is the most frequently used blocking serum — in IHC, IF, Western blot, and ELISA.
Endogenous rabbit IgG present in tissue sections or on membranes is detected by anti-rabbit secondary antibodies as a false-positive signal. Blocking with NRS saturates these sites in advance, eliminating non-specific background that cannot be removed by washing.
Applications of Normal Rabbit Serum (NRS)
| Application | Standard Protocol | Why NRS? |
|---|---|---|
| IHC / IFA Blocking | 5–10% NRS in PBS-T, 30–60 min RT before anti-rabbit secondary | Saturates endogenous rabbit IgG in tissue — prevents non-specific background |
| Western Blot Blocking | 5% NRS in TBST as blocking buffer | Alternative to BSA/milk — preferred for phospho-protein blots where BSA phosphorylation causes cross-reactivity |
| ELISA Plate Blocking | 2–5% NRS to block uncoated binding sites | Reduces background OD in sandwich ELISA formats |
| Antibody Diluent | 0.5–1% NRS in PBS-T | Stabilises rabbit primary antibodies during long incubations |
| Complement Studies | Native NRS as complement source | C1–C9 active in non-heat-inactivated lots |
Technical Specifications
| Parameter | Specification |
|---|---|
| Species | Rabbit (Oryctolagus cuniculus) |
| Abbreviation | NRS — Normal Rabbit Serum |
| Collection | Pooled healthy donors, sterile bleed |
| Filtration | 0.2 µm sterile filtered |
| Origin | EU |
| Storage | −20 °C; aliquoting recommended |
| Volumes | 100 mL, 500 mL | Bulk on request |
| Documentation | CoA, CoO on request |
| Options | Heat inactivated (56 °C, 30 min) on request |
Frequently Asked Questions
Why must I use rabbit serum when working with anti-rabbit secondary antibodies?
Anti-rabbit secondary antibodies detect any rabbit IgG — including endogenous rabbit IgG present in the tissue or on the membrane. Blocking with NRS saturates these sites with rabbit immunoglobulins before adding the secondary, preventing false-positive signal that cannot be removed by washing.
Heat inactivated or native NRS — which for IHC blocking?
Heat inactivated (HI) NRS is standard for IHC blocking — complement activity is irrelevant for blocking applications and HI improves lot consistency. For complement studies, use native (non-HI) NRS.
What concentration for Western blot blocking?
5% NRS in TBST for 60 minutes at RT or overnight at 4 °C. NRS is superior to BSA for phospho-protein blots because BSA is itself phosphorylated and can cause anti-phospho antibody cross-reactivity.
Complete Animal Serum Portfolio at SeamlessBio
All 9 animal sera from one EU source — consistent documentation, no minimum order.
| Species | Abbr. | Primary Application |
|---|---|---|
| Rabbit | NRS | IHC/WB/ELISA blocking — anti-rabbit secondary antibodies |
| Goat | NGS | IHC/IF blocking — most common secondary antibody host |
| Sheep | NSS | Blocking, complement CFT, vaccine & vet diagnostics |
| Mouse | NMS | ELISA controls, anti-mouse IHC, primary cell culture |
| Rat | — | Anti-rat IHC blocking, rat primary cell culture |
| Horse | DHS | PC12 differentiation, hybridoma, muscle differentiation |
| Chicken | NCS | CEF cell culture, poultry ELISA controls |
| Pig | NPS | Swine vaccine development, porcine vet diagnostics |
| Guinea Pig | NGPS | CFT complement source — unique diagnostic niche |
Order Information
| Parameter | Details |
|---|---|
| Shop URL | shop.seamlessbio.de/en/products/rabbit-serum |
| Volumes | 100 mL, 500 mL | Bulk on request |
| Documentation | CoA, CoO on request — free with every order |
| Free test volume | Available before purchase — contact us |
| Batch reservation | Yes — reserve one lot for your entire project |
| info@seamlessbio.de | |
| Phone | +49 851 37932226 |